R&S®SML / R&S®SMV03 Test sequence
1147.7621.12 10.47 E-6
I/Q Imbalance
Measurement of Imbalance
Test equipment Spectrum analyzer (Table 5-1, item 2)
Adjustable DC voltage source (Table 5-1, item 12).
Test setup Connect the spectrum analyzer to the RF output of the R&S SMV03.
Connect the DC voltage source to the I or the Q input.
Measurement Settings on the R&S SMV03
Test frequencies: 250MHz, 250MHz+0.1Hz, 420MHz,
420MHz+0.1Hz, 665MHz, 900 MHz, 1170MHz, 1900MHz,
3000MHz
Test level 0 dBm
Select State IQ in the menu vector Mod.
Settings on analyzer
Center frequency = test frequency., Span 1 MHz
Reference level = test level +3 dB
Scale 1 dB/div.
First measure the undistorted level as a reference. To this end,
apply a DC voltage of 0.500 V to the I and then to the Q and note
down the corresponding RF levels as reference levels. In the menu
Vector Mod/Impairment State select On and Imbalance 10 %.
repeat the Level measurement.
The I level should increase by the set imbalance, the Q level
decrease by the inverse ratio. With 10 %, the I level should
increase to 1.1 times, the Q level should be reduced to 0.909 times
the original value (corresponding to ±0.83 dB).
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